The border bill was not what the GOP was asking for. It was a compromise and not enough of one to get the deal done with the most fringe of that party.
It is quite literally what the GOP asked for not even 12 weeks ago (Dec 6, 2023):
> Republicans on Wednesday blocked an emergency spending bill to fund the war in Ukraine, demanding strict new border restrictions in exchange and severely jeopardizing President Biden’s push to replenish the war chests of American allies before the end of the year.
The Democrats said okay. Senators Sinema, Lankford (literally the 2nd most conservative senator according to his own congressional page), and Murphy spent the last couple months negotiating a new bill.
Trump then tanked it saying it would help Biden:
> Republican front-runner Donald Trump said he wants to be held responsible for blocking a bipartisan border security bill in the works in the Senate as President Biden seeks emergency authority to rein in a record surge of unauthorized border crossings.
We are a divided house.